The previous guide is about how to search apps in Windows Store. Now you ask “how many free Windows Store apps are there and how to find all of them in Windows Store?”.
I am not the insider or Windows Store administrator, but everyone can tell the ballpark figure via Search charm in Windows 8. This figure should be varying from time to time and might also be different between countries, system locales, Windows 8 editions, etc.

During my search just a couple of minutes ago, there are 8855 free Windows Store apps available.

If my eyesight is good and reliable, this 8.8K figure excludes the Desktop app (there are total 10981 apps + programs, both free and paid-ware, in Windows Store).

Search for latest free apps in Windows Store

1. Open Windows Store and press Windows+Q for Search charm to type an asterisk (*) then hit ENTER key.

2. Now in the Search result screen, select “All categories”, “Free”, and “Sort by newest” options – there you are, all the free Windows Store apps available to your Windows 8.

Note, if later Microsoft disables the use of wildcard character (e.g. asterisk) as search term, this trick is definitely not working.